Add abort API in gloo ProcessGroup Send/Recv Work (#29928)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29928
Original author: Shihao Xu
- Add abort to `c10d::ProcessGroup::Work`.
- Change the return type of `c10d::ProcessGroup::Work::wait()` to boolean to indicate if the work is aborted after waiting.
- Add unit test for the correctness of abort.
ghstack-source-id: 94305515
ghstack-source-id: 94305515
Differential Revision: D5685727
fbshipit-source-id: 6e682bb563c2393a5c303c877331140417d3f607
